On the psychophysics of arm-positioning movements

The basis for the relationship between physical stimulus and magnitude of psychological response in angular movements of the upper limbs was investigated. Participants compared movements to a standard location with movements to comparison locations and movements of a standard distance with movements of comparison distances. The results add to the controversy surrounding the explanations for the differences in psychological response magnitude of movements to locations and movements across distances. Data obtained from movements to locations and movements across distances indicated similar Weber ratios but different patterns for the just noticeable differences. The data of this and previous research suggest that the application of a prothetic continuum to arm movements is inappropriate. An alternative explanation of the differences in the perception of movements to locations and movements across distances is offered.